Novel cyclic phosphinate derivatives and method of preparing the same

ABSTRACT

Provided are novel cyclic phosphinate derivatives and a method of preparing the same, and more particularly, cyclic phosphinate derivatives including benzoxaphosphole oxide derivatives and benzoxaphosphorin oxide derivatives, and a method of preparing the same. The cyclic phosphinate derivative according to the present invention may have pharmacological and physiological activities, be used as the basic skeleton of the natural material, and be used in development of a new drug, and synthesis of various medicines. In addition, with the method of preparing a cyclic phosphinate derivative according to the present invention, various cyclic phosphinate derivatives may be prepared with high yield through a simple synthetic process by performing an intramolecular carbon-oxygen coupling reaction on the phosphinic acid derivative in the presence of a palladium (Pd) catalyst, an oxidant, and a base.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a divisional application of U.S. patentapplication Ser. No. 14/598,143 entitled “Novel Cyclic PhosphinateDerivatives and Method of Preparing the Same,” filed on Jan. 15, 2015,which claims priority under 35 U.S.C. §119 to Korean Patent ApplicationNo. 10-2014-0053257, filed on May 2, 2014, in the Korean IntellectualProperty Office, the entire contents of each of which are herebyincorporated by reference in their entirety for all purposes.

TECHNICAL FIELD

The following disclosure relates to novel cyclic phosphinate derivativesand a method of preparing the same, and more particularly, to cyclicphosphinate derivatives including benzoxaphosphole oxide derivatives andbenzoxaphosphorin oxide derivatives, and a method of preparing the same.

BACKGROUND

Heterocyclic compounds configure a basic skeleton of a natural material,and among them, organic phosphorus compounds have pharmacological andphysiological activities, such that the organic phosphorus compounds areimportant compounds in pharmaceutical, material, and crop protectionagent fields.

Among them, since benzoxaphosphole oxide compounds have physiologicalactivities and may be used as an important raw material or intermediatein agricultural and material chemistry fields in addition to being usedin synthesizing a new medicine, an interest in synthesis methods thereofhave increased. Therefore, synthesis methods of benzoxaphosphole oxidederivatives as described above have been reported (Chem. Rev. 2003, 103,3029). Up to now, the methods of synthesizing benzoxaphosphole oxidehave a disadvantage in that benzoxaphosphole oxide is synthesizedthrough several steps.

Meanwhile, a dibenzoxaphosphorin oxide derivative is a lactonederivative including phosphorus. It was known that uses of lactone arevarious, and various application methods and synthesis methods have beenreported (J. Org. Chem. 2007, 72, 9379-9382). In addition, it has beenwell known that lactone has physiological activities, and since lactoneis used as a basic skeleton of a natural material, even in the case inwhich phosphorus is contained, it is expected that the lactonederivative will have physiological activities or be variously appliedthrough additional steps. However, the number of reported compounds inwhich phosphorus is contained is small, and particularly, there is noreported compound in which various substituents are contained(Transition Met. Chem. 2008, 33, 505-510). In addition, recently,research into a method of synthesizing a carbon-carbon, carbon-nitrogen,or carbon-oxygen bond by using various transition metal catalyststhrough a carbon-hydrogen bond activation reaction with a directinggroup has been conducted. This reaction is characterized in that variousbonds may be introduced by interaction between the catalyst and thedirecting group without pre-functionalization. Recently, it has beenreported that various bonds are formed by using a directing groupcontaining phosphorus through the carbon-hydrogen bond activationreaction with a transition metal (Org. Lett. 2013, 15, 3358-3361; Org.Lett. 2013, 15, 3986-3989). In addition, a method of forming acarbon-oxygen bond to synthesize a cyclic compound is a good method ofsynthesizing a novel heterocyclic compound (Org. Lett. 2013, 15,5210-5213).

However, the case of synthesizing a benzoxaphosphole oxide derivativeand a dibenzoxaphosphorin oxide derivative by using the transition metalcatalyst through the carbon-hydrogen bond activation reaction has notyet been reported. Therefore, it is important to develop an efficientC—H bond activation reaction using a directing group associated withphosphorus.

The present invention relates to a new method of synthesizing abenzoxaphosphole oxide derivative and a dibenzoxaphosphorin oxidederivative having a short reaction step. The method of preparing abenzoxaphosphole oxide derivative and a dibenzoxaphosphorin oxidederivative according to the present invention has an advantage in thatbenzoxaphosphole oxide derivatives and dibenzoxaphosphorin oxidederivatives in which various substituents are introduced by anintramolecular carbon-oxygen coupling reaction due to the carbon (sp² orsp³)-hydrogen bond activation reaction may be prepared from a phosphinicacid derivative in the presence of a palladium catalyst.

SUMMARY

An embodiment of the present invention is directed to providing a novelcyclic phosphinate derivative having pharmacological and physiologicalactivities.

Another embodiment of the present invention is directed to providing amethod of preparing a novel cyclic phosphinate derivative.

In one general aspect, there is provided a cyclic phosphinate derivativerepresented by the following Chemical Formula 1.

In Chemical Formula 1,

R¹ to R⁴ are each independently hydrogen, (C1-C20)alkyl,halo(C1-C20)alkyl, (C1-C20)alkoxy, (C6-C20)aryl, halogen,(C6-C20)aryloxy, or tri(C1-C20)alkylsilyl; when X is

Y is O, or when X is O, Y is

R⁵ is (C1-C20)alkyl, (C1-C20)alkoxy or (C6-C20)aryl;

Z is —CR¹¹R¹²— or —CR¹³═CR¹⁴—;R¹¹ and R¹² are each independently hydrogen or (C1-C20)alkyl, or arelinked to each other by (C1-C7)alkylene to form a spiro ring;R¹¹ and R¹² are linked to each other by —CR²¹═CR²²—CR²³═CR²⁴— or-L-CR²⁵═CR²⁶— to form a fused ring;R²¹ to R²⁶ are each independently hydrogen, (C1-C20)alkyl,halo(C1-C20)alkyl, (C1-C20)alkoxy, (C6-C20)aryl, or halogen, or arelinked to a substituent adjacent thereto by (C1-C7)alkylene,(C2-C7)alkenylene, or (C4-C7)alkanedienylene to form a fused ring;

L is O or S; and

alkyl and aryl of R¹ to R⁵ are further substituted with one or moresubstituents selected from the group consisting of halogen,(C1-C20)alkyl, (C1-C20)alkoxy, and halo(C1-C20)alkyl, respectively.

In another general aspect, there is provided a method of preparing acyclic phosphinate derivative represented by Chemical Formula 1characterized by performing an intramolecular carbon-oxygen couplingreaction on a phosphinic acid derivative represented by the followingChemical Formula 6 or 7 in the presence of a palladium (Pd) catalyst, anoxidant, and a base to prepare a cyclic phosphinate derivativerepresented by the following Chemical Formula 2 or 3.

Hereinafter, the present invention will be described in detail.

Here, technical terms and scientific terms used in the presentspecification have the general meaning understood by those skilled inthe art to which the present invention pertains unless otherwisedefined. In addition, repetitive descriptions of the same technicalconfiguration and action as those in the related art will be omitted.

The present invention may provide a cyclic phosphinate derivativerepresented by the following Chemical Formula 1:

In Chemical Formula 1,

R¹ to R⁴ are each independently hydrogen, (C1-C20)alkyl,halo(C1-C20)alkyl, (C1-C20)alkoxy, (C6-C20)aryl, halogen,(C6-C20)aryloxy, or tri(C1-C20)alkylsilyl;when X is

Y is O, or when X is O, Y is

R⁵ is (C1-C20)alkyl, (C1-C20)alkoxy or (C6-C20)aryl;

Z is —CR¹¹R¹²— or —CR¹³═CR¹⁴—;R¹¹ and R¹² are each independently hydrogen, or (C1-C20)alkyl, or arelinked to each other by (C1-C7)alkylene to form a spiro ring;R¹³ and R¹⁴ are linked to each other by —CR²¹═CR²²—CR²³═CR²⁴— or-L-CR²⁵═CR²⁶— to form a fused ring;R²¹ to R²⁶ are each independently hydrogen, (C1-C20)alkyl,halo(C1-C20)alkyl, (C1-C20)alkoxy, (C6-C20)aryl, or halogen, or arelinked to a substituent adjacent thereto by (C1-C7)alkylene,(C2-C7)alkenylene, or (C4-C7)alkanedienylene to form a fused ring;

L is O or S; and

alkyl and aryl of R¹ to R⁵ are further substituted with one or moresubstituents selected from the group consisting of halogen,(C1-C20)alkyl, (C1-C20)alkoxy, and halo(C1-C20)alkyl, respectively.

The terms ┌alkyl┘ and ┌alkoxy┘ disclosed herein include both of thestraight chain type and the branched chain type.

The term ┌aryl┘ disclosed herein, which is an organic radical derivedfrom aromatic hydrocarbon by removing one hydrogen atom therefrom,includes a single ring or a fused ring containing, properly 4 to 7 ringatoms, and preferably 5 or 6 ring atoms in each ring, and include formsin which two or more aryls are combined through single bond(s). Specificexamples of aryl include aromatic groups such as phenyl, naphthyl,biphenyl, indenyl, fluorenyl, phenanthrenyl, anthracenyl, triphenylenyl,pyrenyl, chrysenyl, and naphthacenyl.

The novel cyclic phosphinate derivative represented by Chemical Formula1 may include a benzoxaphosphole oxide derivative and abenzoxaphosphorin oxide derivative, and may be, preferably, representedby the following Chemical Formula 2 or 3:

In Chemical Formulas 2 and 3, R¹ to R⁴ and R⁵ have the same definitionsas defined in Chemical Formula 1;

Z is CH₂— or —CR¹³═CR¹⁴—;R¹¹ and R¹² are each independently (C1-C20)alkyl, or are linked to eachother by (C1-C7)alkylene to form a spiro ring;R¹³ and R¹⁴ are linked to each other by —CR²¹═CR²²═CR²³═C²⁴— or-L-CR²⁵═CR²⁶— to form a fused ring;R²¹ to R²⁶ are each independently hydrogen, (C1-C20)alkyl,(C1-C20)alkoxy, (C6-C20)aryl, or halogen, or R²¹ to R²⁴ are linked to asubstituent adjacent thereto by (C1-C7)alkylene or(C4-C7)alkanedienylene to form a fused ring;

L is O or S; and

alkyl and aryl of R¹ to R⁵ are further substituted with one or moresubstituents selected from the group consisting of halogen,(C1-C20)alkyl, (C1-C20)alkoxy, and halo(C1-C20)alkyl, respectively.

In detail, in Chemical Formulas 2 and 3, preferably, R¹ to R⁴ may beeach independently hydrogen, methyl, ethyl, propyl, butyl, pentyl,hexyl, trifluoromethyl, methoxy, ethoxy, propoxy, butoxy, pentyloxy,hexyloxy, phenyl, naphthyl, fluorenyl, chloro, bromo, fluoro, ortrimethylsilyl (TMS), phenyl, naphthyl, or fluorenyl of R¹ to R⁴ beingfurther substituted with one or more substituents selected from thegroup consisting of chloro, bromo, fluoro, methyl, ethyl, propyl, butyl,pentyl, hexyl, methoxy, ethoxy, propoxy, butoxy, pentyloxy, hexyloxy,and trifluoromethyl; R⁵ may be methyl, ethyl, propyl, butyl, pentyl,hexyl, methoxy, ethoxy, propoxy, butoxy, pentyloxy, hexyloxy, phenyl, ornaphthyl, phenyl or naphthyl of R⁵ being further substituted with one ormore substituents selected from the group consisting of chloro, bromo,fluoro, methyl, ethyl, propyl, butyl, pentyl, hexyl, methoxy, ethoxy,propoxy, butoxy, pentyloxy, hexyloxy, and trifluoromethyl; Z may be—CH₂—,

R¹¹ and R¹² may be each independently methyl, ethyl, propyl, butyl,pentyl, or hexyl, or be linked to each other by butylene or pentylene toform a Spiro ring; R²¹ to R²⁶ may be each independently hydrogen,methyl, ethyl, propyl, butyl, pentyl, hexyl, methoxy, ethoxy, propoxy,butoxy, pentyloxy, hexyloxy, phenyl, naphthyl, chloro, bromo, or fluoro;and L may be O or S.

The cyclic phosphinate derivative according to the present invention maybe selected from the following compounds, but is not limited thereto.

Hereinafter, the method of preparing a cyclic phosphinate derivativeaccording to the present invention will be described in detail.

The present invention provides a method of preparing a cyclicphosphinate derivative characterized by performing an intramolecularcarbon-oxygen coupling reaction on a phosphinic acid derivativerepresented by the following Chemical Formula 6 to prepare a cyclicphosphinate derivative represented by the following Chemical Formula 2in the presence of a palladium (Pd) catalyst, an oxidant, and a base:

In Chemical Formulas 2 and 6,

R¹ to R⁴ are each independently hydrogen, (C1-C20)alkyl,halo(C1-C20)alkyl, (C1-C20)alkoxy, (C6-C20)aryl, halogen,(C6-C20)aryloxy, or tri(C1-C20)alkylsilyl;

R⁵ is (C1-C20)alkyl, (C1-C20)alkoxy, or (C6-C20)aryl;

Z is CH₂— or —CR¹³═CR¹⁴—;R¹³ and R¹⁴ are linked to each other by —CR²¹═CR²²—CR²³═CR²⁴— or-L-CR²⁵═CR²⁶— to form a fused ring;R²¹ to R²⁶ are each independently hydrogen, (C1-C20)alkyl,(C1-C20)alkoxy, (C6-C20)aryl, or halogen, or R²¹ to R²⁴ are linked to asubstituent adjacent thereto by (C1-C7)alkylene or(C4-C7)alkanedienylene to form a fused ring;

L is O or S; and

alkyl and aryl of R¹ to R⁵ are further substituted with one or moresubstituents selected from the group consisting of halogen,(C1-C20)alkyl, (C1-C20)alkoxy, and halo(C1-C20)alkyl, respectively.

In addition, the present invention provides a method of preparing acyclic phosphinate derivative characterized by performing anintramolecular carbon-oxygen coupling reaction on a phosphinic acidderivative represented by the following Chemical Formula 7 to prepare acyclic phosphinate derivative represented by the following ChemicalFormula 3 in the presence of a palladium (Pd) catalyst, an oxidant, anda base:

In Chemical Formulas 3 and 7,

R¹ to R⁴ are each independently hydrogen, (C1-C20)alkyl,halo(C1-C20)alkyl, (C1-C20)alkoxy, (C6-C20)aryl, halogen,(C6-C20)aryloxy, or tri(C1-C20)alkylsilyl;

R⁵ is (C1-C20)alkyl, (C1-C20)alkoxy, or (C6-C20)aryl;

R¹¹ and R¹² are each independently (C1-C20)alkyl, or are linked to eachother by (C1-C7)alkylene to form a spiro ring; andalkyl and aryl of R¹ to R⁵ are further substituted with one or moresubstituents selected from the group consisting of halogen,(C1-C20)alkyl, (C1-C20)alkoxy, and halo(C1-C20)alkyl, respectively.

The method of preparing a cyclic phosphinate derivative represented byChemical Formula 2 or 3 according to the present invention is asignificantly effective method capable of obtaining a product with highyield and high purity by a simple process under mild conditions in thepresence of the palladium (Pd) catalyst, the oxidant, and the base.

The palladium (Pd) catalyst used in the method of preparing a cyclicphosphinate derivative according to the present invention may be one ora mixture of two or more selected from the group consisting of PdCl₂,PdBr₂, Pd(OAc)₂, Pd(dba)₂, Pd₂(dba)₃, Pd₂dba₃.CHCl₃, Pd(PPh₃)₄,Pd(OTf)₂, Pd(OTf).2H₂O, Pd(TFA)₂, PdCl₂(MeCN)₂, PdCl₂(PPh₃)₂,Pd(dppf)Cl₂ and [PdCl(C₃H₅)]₂. More preferably, Pd(OAc)₂ may be used asthe palladium (Pd) catalyst.

The palladium (Pd) catalyst used in the method of preparing a cyclicphosphinate derivative according to the present invention may be used ina range of 0.01 to 0.5 equivalents with respect to the phosphinic acidderivative represented by Chemical Formula 6 or 7. More preferably, thepalladium (Pd) catalyst may be used in a range of 0.05 to 0.15equivalents. In the case of using the palladium (Pd) catalyst in theabove-mentioned range, the cyclic phosphinate derivative may be preparedwith high yield, and in the case in which an amount of the palladium(Pd) catalyst is out of the range, yield and economic efficiency may bedeteriorated.

As the oxidant used in the method of preparing a cyclic phosphinatederivative according to the present invention, one or a mixture of twoor more selected from the group consisting of copper(I) chloride (CuCl),copper(I) oxide (Cu₂O), copper(II) oxide (CuO), copper(II) acetate(Cu(OAc)₂), copper triflate (Cu(OTf)₂), copper(II) chloride (CuCl₂),copper(I) bromide (CuBr), copper(I) iodide (CuI), copper(II)acetylacetonate (Cu(acac)₂), sliver(II) oxide (Ag₂O), silver(I) oxide(AgO), silver acetate (AgOAc), silver(II) carbonate (Ag₂CO₃), sodiumpersulfate (Na₂S₂O₈), potassium persulfate (K₂S₂O₈), sodium acetate(NaOAc), benzoquinone (BQ), iron(III) chloride (FeCl₃), manganese(III)acetate dihydrate (Mn(OAc)₃.2H₂O), vanadium(V) oxide (V₂O₅)iodosobenzene diacetate (PhI(OAc)₂), bis(trifluoroacetoxy)iodobenzene(PhI(TFA)₂), acetyl hypoiodite (IOAc), ozone, oxygen, (PhCO₂)₂, and2,2,6,6-tetramethyl-1-piperidinyloxy (free radical, TEMPO) may be used.In view of reactivity and yield, it is most preferable that Ag₂CO₃,PhI(OAc)₂, or a mixture thereof is used as the oxidant.

The oxidant used in the method of preparing a cyclic phosphinatederivative according to the present invention may be used in a range of0.1 to 5.0 equivalents with respect to the phosphinic acid derivativerepresented by Chemical Formula 6 or 7. In view of yield and economicefficiency, it is most preferable that 1.0 to 3.0 equivalents of theoxidant is used.

The base used in the method of preparing a cyclic phosphinate derivativeaccording to the present invention may be one or a mixture of two ormore selected from the group consisting of potassium phosphate monobasic[KH₂PO₄], sodium phosphate dibasic dihydrate [Na₂HPO₄.2H₂O], sodiumphosphate dibasic [Na₂HPO₄], sodium carbonate [Na₂CO₃], sodium phosphatemonobasic [NaH₂PO₄], lithium acetate [LiOAc], lithium carbonate[Li₂CO₃], sodium acetate [NaOAc], potassium phosphate dibasic [K₂HPO₄],potassium phosphate tribasic [K₃PO₄], potassium carbonate [K₂CO₃],cesium fluoride [CsF], potassium bicarbonate [KHCO₃], potassiumhydroxide [KOH], potassium fluoride [KF], potassium hexafluorophosphate[KPF₆], potassium acetate [KOAc], sodium fluoride [NaF], cesium acetate[CsOAc], cesium pivalate [CsOPiv], lithium hexafluorophosphate [LiPF₆],lithium phosphate [Li₃PO₄], lithium fluoride [LiF], and lithium iodide[LiI]. Preferably, NaOAc, K₂HPO₄, or KOAc may be used as the base.

The base used in the method of preparing a cyclic phosphinate derivativeaccording to the present invention may be used in a range of 0.5 to 3.0equivalents with respect to the phosphinic acid derivative representedby Chemical Formula 6 or 7. More preferably, the base may be used in arange of 1.0 to 2.5 equivalents.

In the method of preparing a cyclic phosphinate derivative according tothe present invention, a ligand may be further used in order to preparethe cyclic phosphinate derivative represented by Chemical Formula 2,wherein the ligand may be one or a mixture of two or more selected fromthe group consisting of N-acetyl-L-leucine, Boc-Val-OH[N-(tert-butoxycarbonyl)-L-valine], N-Boc-L-isoleucine, Boc-L-leucine,Ac-Gly-OH [N-acetylglycine], N-Boc-L-isoleucine-hemihydrate, Ac-Ala-OH[N-acetyl-L-alanine], Ac-Phe-OH [N-acetyl-L-phenylalanine], pivalicacid, 2-methyl-2-phenylpropanoic acid, adamantane-1-carboxylic acid,(4-CF₃-C₆H₄)₃P, (4-MeO—C₆H₄)₃P, (4-MeO—C₆H₄)₃P, (2,6-di-MeO—C₆H₃)₃P,(2,4,6-tri-MeO—C₆H₂)₃P, Xantphos[4,5-Bis(diphenylphosphino)-9,9-dimethylxanthene], XPhos[2-Dicyclohexylphosphino-2′,4′,6′-triisopropylbiphenyl], CyJohnphos[(2-Biphenyl)dicyclohexylphosphine], SPhos[2-Dicyclohexylphosphino-2′,6′-dimethoxybiphenyl], Johnphos[(2-Biphenyl)di-tert-butylphosphine], DPEphos[Bis[(2-diphenylphosphino)phenyl]ether], DPPP[1,3-Bis(diphenylphosphino)propane], DPPE[1,2-Bis(diphenylphosphino)ethane], DPPF [1,1′-Bis(diphenylphosphino)ferrocene], tri-o-tolylphosphine, and tri-2-furylphosphine. Preferably,N-acetyl-L-leucine or (4-MeO—C₆H₄)₃P may be used as the ligand.

The ligand used in the method of preparing a cyclic phosphinatederivative according to the present invention may be used in a range of0.1 to 1.0 equivalent with respect to the phosphinic acid derivativerepresented by Chemical Formula 6. More preferably, the ligand may beused in a range of 0.1 to 0.5 equivalents.

As a solvent used in the method of preparing a cyclic phosphinatederivative according to the present invention, a general organic solventmay be used, but it is preferable that 1,4-dioxane, dichloromethane(DCM), dichloroethane (DCE), toluene, acetonitrile (MeCN), nitromethane,tetrahydrofuran (THF), chlorobenzene (PhCl), N,N-dimethylformamide(DMF), N,N-dimethylacetamide (DMA), t-butanol (t-BuOH), t-amylalcohol(t-AmOH), xylene, hexafluorobenzene (C₆F₆), bromobenzene (PhBr),trifluoroacetic acid, benzene, or a mixed solvent thereof is used. Morepreferably, dichloroethane (DCE), chlorobenzene (PhCl), or t-butanol(t-BuOH) may be used.

In the method of preparing a cyclic phosphinate derivative according tothe present invention, any reaction temperature may be possible as longas it is a general temperature used in organic synthesis. However, thereaction temperature may be changed depending on a reaction time, areactant, and an amount of a starting material, and in order to preventthe reaction time from being increased or a reaction yield from beingdeteriorated by generation of by-products, a cyclization reaction may beperformed in a temperature range of room temperature to 160° C., andpreferably 80 to 120° C.

The reaction time may be changed depending on the reactant, the amountof the reactant, and the kind and amount of solvent, and the reaction isterminated after confirming that the phosphinic acid derivativerepresented by Chemical Formula 6 or 7, which is the starting material,is completely consumed using thin layer chromatography (TLC), or thelike. When the reaction is completed, after distilling the solvent underreduced pressure, a target material may be separated and purified by ageneral method such as column chromatography, or the like.

DETAILED DESCRIPTION OF EMBODIMENTS

Hereinafter, configurations of the present invention will be describedin detail through Examples, but the following Examples are only toassist in understanding of the present invention. Therefore, the scopeof the present invention is not limited thereto.

Example 1 Preparation of 7-methyl-1-oxo-1-ethoxy-2,1-benzoxaphosphole

After Pd(OAc)₂ (4.5 mg, 10 mol %, 0.1 eq), (4-MeO—C₆H₄)₃P (28.2 mg, 0.08mmol), Ag₂CO₃ (165.4 mg, 0.6 mmol), and K₂HPO₄ (87.2 mg, 0.5 mmol) wereput into a V-vial, 2,6-dimethylphenyl-phosphonic acid monoethyl ester(42.8 mg, 0.2 mmol) as a starting material and PhCL (2.0 mL) as asolvent were added thereto and stirred at 120 r for 12 hours. Afterconfirming that the starting material was completely consumed using TLC,the resultant was extracted with ethylacetate (5 mL×3) and the reactionwas terminated by celite filtration. After removing the solvent, theresultant was separated using column chromatography, thereby obtaining7-methyl-1-oxo-1-ethoxy-2,1-benzoxaphosphole (25.5 mg, 60%)corresponding to the target compound.

¹H NMR (400 MHz, CDCl₃) δ 7.49 (t, J=7.6 Hz, 1H), 7.26-7.23 (m, 1H),7.13-7.11 (m, 1H), 5.29-5.16 (m, 2H), 4.22-4.09 (m, 2H), 2.59 (s, 3H),1.35 (t, J=7.1 Hz, 3H)

Example 2 Preparation of5,7-dimethyl-1-oxo-1-ethoxy-2,1-benzoxaphosphole

A reaction was performed by the same method as in Example 1 except forusing 2,4,6-trimethylphenyl-phosphonic acid monoethyl ester (45.6 mg,0.2 mmol) instead of 2,6-dimethylphenyl-phosphonic acid monoethyl esterof Example 1, thereby obtaining5,7-dimethyl-1-oxo-1-ethoxy-2,1-benzoxaphosphole (36.2 mg, 80%)corresponding to the target compound.

¹H NMR (400 MHz, CDCl₃) δ 7.06 (d, J=5.8 Hz, 1H), 6.92 (s, 1H),5.23-5.11 (m, 2H), 4.21-4.03 (m, 2H), 2.54 (s, 3H), 2.39 (s, 3H), 1.34(t, J=7.1 Hz, 3H)

Example 3 Preparation of5-tert-butyl-7-methyl-1-oxo-1-ethoxy-2,1-benzoxaphosphole

A reaction was performed by the same method as in Example 1 except forusing 2,6-dimethyl-4-t-butylphenyl-phosphonic acid monoethyl ester (54.1mg, 0.2 mmol) instead of 2,6-dimethylphenyl-phosphonic acid monoethylester of Example 1, thereby obtaining5-tert-butyl-7-methyl-1-oxo-1-ethoxy-2,1-benzoxaphosphole (34.3 mg, 64%)corresponding to the target compound.

¹H NMR (400 MHz, CDCl₃) δ 7.26 (d, J=5.8 Hz, 1H), 7.10 (s, 1H),5.27-5.14 (m, 2H), 4.22-4.06 (m, 2H), 2.57 (s, 3H), 1.35 (d, J=7.1 Hz,3H), 1.32 (s, 9H)

Example 4 Preparation of5-methoxy-7-methyl-1-oxo-1-ethoxy-2,1-benzoxaphosphole

A reaction was performed by the same method as in Example 1 except forusing 2,6-dimethyl-4-methoxyphenyl-phosphonic acid monoethyl ester (48.8mg, 0.2 mmol) instead of 2,6-dimethylphenyl-phosphonic acid monoethylester of Example 1, thereby obtaining5-methoxy-7-methyl-1-oxo-1-ethoxy-2,1-benzoxaphosphole (30.0 mg, 62%)corresponding to the target compound.

¹H NMR (400 MHz, CDCl₃) δ 6.70 (d, J=4.0 Hz, 1H), 6.51 (s, 1H),5.16-5.03 (m, 2H), 4.12-3.98 (m, 2H), 3.80 (s, 3H), 2.47 (s, 3H), 1.27(t, J=7.1 Hz, 3H)

Example 5 Preparation of5-phenoxy-7-methyl-1-oxo-1-ethoxy-2,1-benzoxaphosphole

A reaction was performed by the same method as in Example 1 except forusing 2,6-dimethyl-4-phenoxyphenyl-phosphonic acid monoethyl ester (61.3mg, 0.2 mmol) instead of 2,6-dimethylphenyl-phosphonic acid monoethylester of Example 1, thereby obtaining5-phenoxy-7-methyl-1-oxo-1-ethoxy-2,1-benzoxaphosphole (36.5 mg, 60%)corresponding to the target compound.

¹H NMR (400 MHz, CDCl₃) δ 7.40 (t, J=7.9 Hz, 2H), 7.21 (t, J=7.9 Hz,1H), 7.06-7.03 (m, 2H), 6.86-6.85 (m, 1H), 6.61 (s, 1H), 5.19-5.07 (m,2H), 4.22-4.09 (m, 2H), 2.53 (s, 3H), 1.36 (t, J=7.1 Hz, 3H)

Example 6 Preparation of5-(trimethylsilyl)-7-methyl-1-oxo-1-ethoxy-2,1-benzoxaphosphole

A reaction was performed by the same method as in Example 1 except forusing 2,6-dimethyl-4-trimethylsilylphenyl-phosphonic acid monoethylester (57.3 mg, 0.2 mmol) instead of 2,6-dimethylphenyl-phosphonic acidmonoethyl ester of Example 1, thereby obtaining5-(trimethylsilyl)-7-methyl-1-oxo-1-ethoxy-2, 1-benzoxaphosphole (30.1mg, 53%) corresponding to the target compound.

¹H NMR (400 MHz, CDCl₃) δ 7.36 (d, J=6.4 Hz, 1H), 7.25 (d, J=3.0 Hz,1H), 5.30-5.17 (m, 2H), 4.18-4.11 (m, 2H), 2.59 (s, 3H), 1.35 (t, J=7.1Hz, 3H), 0.28 (s, 9H)

Example 7 Preparation of 7-ethyl-1-oxo-1-ethoxy-2,1-benzoxaphosphole

A reaction was performed by the same method as in Example 1 except forusing 2-methyl-6-ethylphenyl-phosphonic acid monoethyl ester (45.6 mg,0.2 mmol) instead of 2,6-dimethylphenyl-phosphonic acid monoethyl esterof Example 1, thereby obtaining7-ethyl-1-oxo-1-ethoxy-2,1-benzoxaphosphole (19.5 mg, 43%) correspondingto the target compound.

¹H NMR (400 MHz, CDCl₃) δ 7.52 (td, J₁=11.4, J₂=1.2 Hz, 1H), 7.29 (t,J=6.9 Hz, 1H), 7.14-7.11 (m, 1H), 5.29-5.16 (m, 2H), 4.23-4.08 (m, 2H),2.93 (q, J=7.6 Hz, 2H), 1.34 (t, J=7.7 Hz, 6H)

Example 8 Preparation of7-tert-butyl-5-methyl-1-oxo-1-methoxy-2,1-benzoxaphosphole

A reaction was performed by the same method as in Example 1 except forusing 2,4-dimethyl-6-t-butylphenyl-phosphonic acid monoethyl ester (51.3mg, 0.2 mmol) instead of 2,6-dimethylphenyl-phosphonic acid monoethylester of Example 1, thereby obtaining7-tert-butyl-5-methyl-1-oxo-1-methoxy-2,1-benzoxaphosphole (28.5 mg,56%) corresponding to the target compound.

¹H NMR (400 MHz, CDCl₃) δ 7.29 (d, J=6.8 Hz, 1H), 6.93 (s, 1H),5.22-5.12 (m, 2H), 3.71 (d, J=11.9 Hz, 3H), 2.41 (s, 3H), 1.51 (s, 9H)

Example 9 Preparation of4,6,7-trimethyl-1-oxo-1-ethoxy-2,1-benzoxaphosphole

A reaction was performed by the same method as in Example 1 except forusing 2,3,5,6-tetramethylphenyl-phosphonic acid monoethyl ester (48.5mg, 0.2 mmol) instead of 2,6-dimethylphenyl-phosphonic acid monoethylester of Example 1, thereby obtaining4,6,7-trimethyl-1-oxo-1-ethoxy-2,1-benzoxaphosphole (25.9 mg, 54%)corresponding to a target compound.

¹H NMR (400 MHz, CDCl₃) δ 7.15 (s, 1H), 5.18-5.04 (m, 2H), 4.21-4.05 (m,2H), 2.46 (s, 3H), 2.29 (s, 3H), 2.16 (s, 3H), 1.34 (t, J=7.1 Hz, 3H)

Example 10 Preparation of6-bromo-5,7-dimethyl-1-oxo-1-ethoxy-2,1-benzoxaphosphole and4-bromo-5,7-dimethyl-1-oxo-1-ethoxy-2,1-benzoxaphosphole

A reaction was performed by the same method as in Example 1 except forusing 3-bromo-2,4,6-trimethylphenyl-phosphonic acid monoethyl ester(61.4 mg, 0.2 mmol) instead of 2,6-dimethylphenyl-phosphonic acidmonoethyl ester of Example 1, thereby obtaining 6-bromo-5, 7-dimethyl-1-oxo-1-ethoxy-2, 1-benzoxaphosphole and 4-bromo-5, 7-dimethyl-1-oxo-1-ethoxy-2,1-benzoxaphosphole at a ratio of 2:1 (38.4 mg,63%) corresponding to the target compounds.

6-Bromo-5,7-dimethyl-1-oxo-1-ethoxy-2,1-benzoxaphosphole: ¹H NMR (400MHz, CDCl₃) δ 7.04 (d, J=3.4 Hz, 1H), 5.20-5.07 (m, 2H), 4.23-4.07 (m,2H), 2.64 (s, 3H), 2.49 (s, 3H), 1.35 (t, J=7.1 Hz, 3H)

4-Bromo-5,7-dimethyl-1-oxo-1-ethoxy-2,1-benzoxaphosphole: ¹H NMR (400MHz, CDCl₃) δ 7.15 (d, J=6.7 Hz, 1H), 5.15-5.02 (m, 2H), 4.19-4.09 (m,2H), 2.51 (s, 3H), 2.44 (s, 3H), 1.35 (t, J=7.0 Hz, 3H)

Example 11 Preparation of 7-methyl-1-oxo-1-methyl-2,1-benzoxaphosphole

A reaction was performed by the same method as in Example 1 except forusing methyl-(2,6-dimethylphenyl)-phosphinic acid (36.8 mg, 0.2 mmol)instead of 2,6-dimethylphenyl-phosphonic acid monoethyl ester of Example1, thereby obtaining 7-methyl-1-oxo-1-methyl-2,1-benzoxaphosphole (29.5mg, 81%) corresponding to the target compound.

¹H NMR (400 MHz, CDCl₃) δ 7.48 (t, J=7.6 Hz, 1H), 7.24 (t, J=6.3 Hz,1H), 7.14 (d, J=7.6 Hz, 1H), 5.46-5.21 (m, 2H), 2.62 (s, 3H), 1.84 (d,J=14.6 Hz, 3H)

Example 12 Preparation of 5,7-dimethyl-1-oxo-1-methyl-2,1-benzoxaphosphol e

A reaction was performed by the same method as in Example 1 except forusing methyl-(2,4,6-trimethylphenyl)-phosphinic acid (39.6 mg, 0.2 mmol)instead of 2,6-dimethylphenyl-phosphonic acid monoethyl ester of Example1, thereby obtaining 5,7-dimethyl-1-oxo-1-methyl-2,1-benzoxaphosphole(34.1 mg, 87%) corresponding to the target compound.

¹H NMR (400 MHz, CDCl₃) δ 7.05 (d, J=5.0 Hz, 1H), 6.94 (s, 1H),5.41-5.16 (m, 2H), 2.57 (s, 3H), 2.39 (s, 3H), 1.81 (d, J=14.6 Hz, 3H)

Example 13 Preparation of 4,6,7-trimethyl-1-oxo-1-methyl-2,1-benzoxaphosphol e

A reaction was performed by the same method as in Example 1 except forusing methyl-(2,3,5,6-tetramethylphenyl)-phosphinic acid (42.4 mg, 0.2mmol) instead of 2,6-dimethylphenyl-phosphonic acid monoethyl ester ofExample 1, thereby obtaining4,6,7-trimethyl-1-oxo-1-methyl-2,1-benzoxaphosphole (23.5 mg, 56%)corresponding to the target compound.

¹H NMR (400 MHz, CDCl₃) δ 7.14 (s, 1H), 5.35-5.10 (m, 2H), 2.49 (s, 3H),2.29 (s, 3H), 2.18 (s, 3H), 1.81 (d, J=14.5 Hz, 3H)

Example 14 Preparation of 7-methyl-1-oxo-1-phenyl-2,1-benzoxaphosphole

A reaction was performed by the same method as in Example 1 except forusing phenyl-(2,6-dimethylphenyl)-phosphinic acid (49.2 mg, 0.2 mmol)instead of 2,6-dimethylphenyl-phosphonic acid monoethyl ester of Example1, thereby obtaining 7-methyl-1-oxo-1-phenyl-2,1-benzoxaphosphole (28.3mg, 58%) corresponding to the target compound.

¹H NMR (400 MHz, CDCl₃) δ 7.76-7.70 (m, 2H), 7.58-7.44 (m, 3H),7.23-7.17 (m, 2H), 5.62-5.39 (m, 2H), 2.36 (s, 3H)

Example 15 Preparation of5,7-dimethyl-1-oxo-1-phenyl-2,1-benzoxaphosphole

A reaction was performed by the same method as in Example 1 except forusing phenyl-(2,4,6-trimethylphenyl)-phosphinic acid (52.1 mg, 0.2 mmol)instead of 2,6-dimethylphenyl-phosphonic acid monoethyl ester of Example1, thereby obtaining 5,7-dimethyl-1-oxo-1-phenyl-2,1-benzoxaphosphole(32.0 mg, 62%) corresponding to the target compound.

¹H NMR (400 MHz, CDCl₃) δ 7.74-7.69 (m, 2H), 7.56-7.52 (m, 1H),7.47-7.43 (m, 2H), 7.01-7.00 (m, 2H), 5.56-5.33 (m, 2H), 2.40 (s, 3H),2.32 (s, 3H)

Example 16 Preparation of7-methyl-1-oxo-1-(2,6-dimethylphenyl)-2,1-benzoxaphosphole

A reaction was performed by the same method as in Example 1 except forusing bis(2,6-dimethylphenyl)-phosphinic acid (54.9 mg, 0.2 mmol)instead of 2,6-dimethylphenyl-phosphonic acid monoethyl ester of Example1, thereby obtaining7-methyl-1-oxo-1-(2,6-dimethylphenyl)-2,1-benzoxaphosphole (12.0 mg,22%) corresponding to the target compound.

¹H NMR (400 MHz, CDCl₃) δ 7.46 (td, J₁=7.5, J₂=1.0 Hz, 1H), 7.31 (td,J₁=15.2, J_(2=1.6) Hz, 1H), 7.20-7.15 (m, 2H), 7.11-7.07 (m, 2H),5.68-5.33 (m, 2H), 2.43 (s, 6H), 2.28 (s, 3H)

Example 17 Preparation of3,3-dimethyl-2-oxo-2-ethoxy-1,2-benzoxaphosphole

After Pd(OAc)₂ (4.5 mg, 10 mol %, 0.1 eq), PhI(OAc)₂ (99.6 mg, 0.3mmol), and NaOAc (16.4 mg, 0.2 mmol) were put into a V-vial,dimethylbenzylphosphonic acid monoethyl ester (45.6 mg, 0.2 mmol) as astarting material and DCE (2.0 mL) as a solvent were added thereto andstirred at 80 r for 20 hours. After confirming that the startingmaterial was completely consumed using TLC, the resultant was extractedwith ethylacetate (5 mL×3) and the reaction was terminated by celitefiltration. After removing the solvent, the resultant was separatedusing column chromatography, thereby obtaining3,3-dimethyl-2-oxo-2-ethoxy-1,2-benzoxaphosphole (39.4 mg, 87%)corresponding to the target compound.

¹H NMR (400 MHz, CDCl₃) δ 7.24-7.16 (m, 2H), 7.11-7.06 (m, 1H),7.01-6.99 (m, 1H), 4.35-4.26 (m, 2H), 1.52 (dd, J=17.6, 3.9 Hz, 6H),1.36 (t, J=7.1 Hz, 3H)

Example 18 Preparation of3,3-diethyl-2-oxo-2-ethoxy-1,2-benzoxaphosphole

A reaction was performed by the same method as in Example 17 except forusing diethylbenzylphosphonic acid monoethyl ester (51.3 mg, 0.2 mmol)instead of dimethylbenzylphosphonic acid monoethyl ester of Example 17,thereby obtaining 3,3-diethyl-2-oxo-2-ethoxy-1,2-benzoxaphosphole (44.2mg, 87%) corresponding to the target compound.

¹H NMR (400 MHz, CDCl₃) δ 7.24-7.20 (m, 1H), 7.12-7.05 (m, 2H),7.01-7.00 (m, 1H), 4.36-4.23 (m, 2H), 2.07-1.18 (m, 4H), 1.35 (t, J=7.4Hz, 3H), 1.09 (t, J=7.4 Hz, 3H), 0.89 (t, J=7.4 Hz, 3H)

Example 19 Preparation of3,3-dipropyl-2-oxo-2-ethoxy-1,2-benzoxaphosphole

A reaction was performed by the same method as in Example 17 except forusing dipropylbenzylphosphonic acid monoethyl ester (48.0 mg, 0.2 mmol)instead of dimethylbenzylphosphonic acid monoethyl ester of Example 17,thereby obtaining 3,3-dipropyl-2-oxo-2-ethoxy-1,2-benzoxaphosphole (54.2mg, 96%) corresponding to the target compound.

¹H NMR (400 MHz, CDCl₃) δ 7.24-7.19 (m, 1H), 7.13-7.11 (m, 1H),7.08-7.04 (m, 1H), 7.00-6.98 (m, 1H), 4.35-4.21 (m, 2H), 2.00-1.55 (m,5H), 1.48-1.37 (m, 2H), 1.34 (t, J=7.1 Hz, 3H), 1.21-1.08 (m, 1H), 0.99(t, J=7.2 Hz, 3H), 0.86 (t, J=7.3 Hz, 3H)

Example 20 Preparation of3,3-dimethyl-2-oxo-2-ethoxy-4-methyl-1,2-benzoxaphosphole

A reaction was performed by the same method as in Example 17 except forusing 2-(methyl)-dimethylbenzylphosphonic acid monoethyl ester (48.5 mg,0.2 mmol) instead of dimethylbenzylphosphonic acid monoethyl ester ofExample 17, thereby obtaining3,3-dimethyl-2-oxo-2-ethoxy-4-methyl-1,2-benzoxaphosphole (28.8 mg, 60%)corresponding to the target compound.

¹H NMR (400 MHz, CDCl₃) δ 7.10 (t, J=7.9 Hz, 1H), 6.86-6.82 (m, 2H),4.33-4.26 (m, 2H), 2.40 (s, 3H), 1.61 (dd, J=17.6, 15.1 Hz, 6H), 1.36(t, J=7.1 Hz, 3H)

Example 21 Preparation of3,3-dimethyl-2-oxo-2-ethoxy-5-methyl-1,2-benzoxaphosphole

A reaction was performed by the same method as in Example 17 except forusing 3-(methyl)-dimethylbenzylphosphonic acid monoethyl ester (48.5 mg,0.2 mmol) instead of dimethylbenzylphosphonic acid monoethyl ester ofExample 17, thereby obtaining3,3-dimethyl-2-oxo-2-ethoxy-5-methyl-1,2-benzoxaphosphole (34.1 mg, 71%)corresponding to the target compound.

¹H NMR (400 MHz, CDCl₃) δ 7.02-6.97 (m, 2H), 6.89 (d, J=8.1 Hz, 1H),4.34-4.24 (m, 2H), 2.31 (s, 3H), 1.50 (dd, J=17.6, 3.9 Hz, 6H), 1.35 (t,J=7.1 Hz, 3H)

Example 22 Preparation of3,3-dimethyl-2-oxo-2-ethoxy-6-methyl-1,2-benzoxaphosphole

A reaction was performed by the same method as in Example 17 except forusing 4-(methyl)-dimethylbenzylphosphonic acid monoethyl ester (48.5 mg,0.2 mmol) instead of dimethylbenzylphosphonic acid monoethyl ester ofExample 17, thereby obtaining3,3-dimethyl-2-oxo-2-ethoxy-6-methyl-1,2-benzoxaphosphole (40.4 mg, 84%)corresponding to the target compound.

¹H NMR (400 MHz, CDCl₃) δ 7.04 (dd, J=7.7, 1.2 Hz, 1H), 6.91-6.88 (m,1H), 6.82 (s, 1H), 4.34-4.24 (m, 2H), 2.33 (s, 3H), 1.50 (dd, J=17.6,4.0 Hz, 6H), 1.35 (t, J=7.1 Hz, 3H)

Example 23 Preparation of3,3-dimethyl-2-oxo-2-ethoxy-6-tert-butyl-1,2-benzoxaphosphole

A reaction was performed by the same method as in Example 17 except forusing 4-(t-butyl)-dimethylbenzylphosphonic acid monoethyl ester (56.9mg, 0.2 mmol) instead of dimethylbenzylphosphonic acid monoethyl esterof Example 17, thereby obtaining3,3-dimethyl-2-oxo-2-ethoxy-6-tert-butyl-1,2-benzoxaphosphole (46.9 mg,83%) corresponding to the target compound.

¹H NMR (400 MHz, CDCl₃) δ 7.12-7.07 (m, 2H), 7.03 (m, 1H), 4.35-4.26 (m,2H), 1.50 (dd, J=17.6, 2.8 Hz, 6H), 1.37 (t, J=7.1 Hz, 3H), 1.30 (s, 9H)

Example 24 Preparation of3,3-dimethyl-2-oxo-2-ethoxy-5-methoxy-1,2-benzoxaphosphole

A reaction was performed by the same method as in Example 17 except forusing 3-(methoxy)-dimethylbenzylphosphonic acid monoethyl ester (51.7mg, 0.2 mmol) instead of dimethylbenzylphosphonic acid monoethyl esterof Example 17, thereby obtaining3,3-dimethyl-2-oxo-2-ethoxy-5-methoxy-1,2-benzoxaphosphole (34.9 mg,68%) corresponding to the target compound.

¹H NMR (400 MHz, CDCl₃) δ 6.93 (d, J=8.4 Hz, 1H), 6.76-6.72 (m, 2H),4.34-4.24 (m, 2H), 3.78 (s, 3H), 1.51 (dd, J=17.5, 1.5 Hz, 6H), 1.35 (t,J=7.1 Hz, 3H)

Example 25 Preparation of3,3-dimethyl-2-oxo-2-ethoxy-6-methoxy-1,2-benzoxaphosphole

A reaction was performed by the same method as in Example 17 except forusing 4-(methoxy)-dimethylbenzylphosphonic acid monoethyl ester (51.7mg, 0.2 mmol) instead of dimethylbenzylphosphonic acid monoethyl esterof Example 17, thereby obtaining3,3-dimethyl-2-oxo-2-ethoxy-6-methoxy-1,2-benzoxaphosphole (35.9 mg,70%) corresponding to the target compound.

¹H NMR (400 MHz, CDCl₃) δ 7.05 (dd, J=8.4 Hz, 1.4 Hz, 1H), 6.63 (ddd,J=8.5, 2.5, 0.9 Hz, 1H), 6.58 (dd, J=2.4 Hz, 0.9 Hz, 1H), 4.35-4.25 (m,2H), 3.78 (s, 3H), 1.49 (dd, J=17.7, 2.7 Hz, 6H), 1.36 (t, J=7.1 Hz, 3H)

Example 26 Preparation of3,3-dimethyl-2-oxo-2-ethoxy-6-chloro-1,2-benzoxaphosphole

A reaction was performed by the same method as in Example 17 except forusing 4-(chloro)-dimethylbenzylphosphonic acid monoethyl ester (52.5 mg,0.2 mmol) instead of dimethylbenzylphosphonic acid monoethyl ester ofExample 17, thereby obtaining3,3-dimethyl-2-oxo-2-ethoxy-6-chloro-1,2-benzoxaphosphole (32.8 mg, 63%)corresponding to the target compound.

¹H NMR (400 MHz, CDCl₃) δ 7.11-7.06 (m, 2H), 7.03-7.03 (m, 1H),4.36-4.26 (m, 2H), 1.50 (dd, J=17.6, 2.8 Hz, 6H), 1.37 (t, J=7.1 Hz, 3H)

Example 27 Preparation of3,3-dimethyl-2-oxo-2-ethoxy-6-trifluoromethyl-1,2-benzoxaphosphole

A reaction was performed by the same method as in Example 17 except forusing 4-(trifluoromethyl)-dimethylbenzylphosphonic acid monoethyl ester(59.3 mg, 0.2 mmol) instead of dimethylbenzylphosphonic acid monoethylester of Example 17, thereby obtaining3,3-dimethyl-2-oxo-2-ethoxy-6-trifluoromethyl-1,2-benzoxaphosphol e(36.5 mg, 62%) corresponding to the target compound.

¹H NMR (400 MHz, CDCl₃) δ 7.38-7.36 (m, 1H), 7.30-7.28 (m, 1H), 7.26 (s,1H), 4.40-4.29 (m, 2H), 1.54 (dd, J=17.5, 4.9 Hz, 6H), 1.38 (t, J=7.1Hz, 3H)

Example 28 Preparation of3,3-dipropyl-2-oxo-2-ethoxy-6-trifluoromethyl-1,2-benzoxaphosphole

A reaction was performed by the same method as in Example 17 except forusing 4-(trifluoromethyl)-dipropylbenzylphosphonic acid monoethyl ester(70.5 mg, 0.2 mmol) instead of dimethylbenzylphosphonic acid monoethylester of Example 17, thereby obtaining3,3-dipropyl-2-oxo-2-ethoxy-6-trifluoromethyl-1,2-benzoxaphosphole (48.5mg, 65%) corresponding to the target compound.

¹H NMR (400 MHz, CDCl₃) δ 7.35-7.33 (m, 1H), 7.26-7.23 (m, 2H),4.38-4.24 (m, 2H), 2.02-1.57 (m, 5H), 1.46-1.37 (m, 2H), 1.36 (t, J=7.1Hz, 3H), 1.20-1.10 (m, 1H), 0.98 (t, J=7.2 Hz, 3H), 0.88 (t, J=7.3 Hz,3H)

Example 29 Preparation of3-cyclopentyl-2-oxo-2-ethoxy-1,2-benzoxaphosphole

A reaction was performed by the same method as in Example 17 except forusing 1-phenylcyclopentylphosphonic acid ethyl ester (50.9 mg, 0.2 mmol)instead of dimethylbenzylphosphonic acid monoethyl ester of Example 17,thereby obtaining 3-cyclopentyl-2-oxo-2-ethoxy-1,2-benzoxaphosphole(40.4 mg, 80%) corresponding to a target compound.

¹H NMR (400 MHz, CDCl₃) δ 7.21-7.15 (m, 2H), 7.08-7.04 (m, 1H),6.98-6.96 (m, 1H), 4.34-4.24 (m, 2H), 2.71-2.60 (m, 1H), 2.46-2.37 (m,1H), 2.04-1.82 (m, 5H), 1.79-1.66 (m, 1H), 1.36 (t, J=7.1 Hz, 3H)

Example 30 Preparation of3-cyclohexyl-2-oxo-2-ethoxy-1,2-benzoxaphosphole

A reaction was performed by the same method as in Example 17 except forusing 1-phenylcyclohexylphosphonic acid ethyl ester (53.8 mg, 0.2 mmol)instead of dimethylbenzylphosphonic acid monoethyl ester of Example 17,thereby obtaining 3-cyclohexyl-2-oxo-2-ethoxy-1,2-benzoxaphosphole (45.3mg, 85%) corresponding to a target compound.

¹H NMR (400 MHz, CDCl₃) δ 7.22-7.15 (m, 2H), 7.08-7.04 (m, 1H),6.98-6.96 (m, 1H), 4.37-4.27 (m, 2H), 2.25-2.17 (m, 1H), 2.15-2.09 (m,1H), 2.07-2.00 (m, 1H), 1.90-1.80 (m, 2H), 1.78-1.71 (m, 2H), 1.64-1.45(m, 2H), 1.39-1.29 (m, 1H), 1.36 (t, J=7.1 Hz, 3H)

Example 31 Preparation of3-ethyl-3-methyl-2-oxo-2-ethoxy-1,2-benzoxaphosphole

A reaction was performed by the same method as in Example 17 except forusing ethylmethylbenzylphosphonic acid monoethyl ester (48.5 mg, 0.2mmol) instead of dimethylbenzylphosphonic acid monoethyl ester ofExample 17, thereby obtaining3-ethyl-3-methyl-2-oxo-2-ethoxy-1,2-benzoxaphosphole (40.4 mg, 84%,diastereomeric ratio=2:1) corresponding to the target compound.

¹H NMR (400 MHz, CDCl₃) data for the major isomer; δ 7.25-7.19 (m, 1H),7.15-7.11 (m, 1H), 7.10-7.05 (m, 1H), 7.01-6.99 (m, 1H), 4.36-4.23 (m,2H), 1.98-1.79 (m, 2H), 1.50 (d, J=17.8 Hz, 3H), 1.37 (t, J=7.1 Hz, 3H),1.10 (t, J=7.5 Hz, 3H); data for the minor isomer; δ 7.25-7.19 (m, 1H),7.15-7.11 (m, 1H), 7.10-7.05 (m, 1H), 7.01-6.99 (m, 1H), 4.36-4.23 (m,2H), 1.98-1.79 (m, 2H), 1.50 (d, J=17.8 Hz, 3H), 1.34 (t, J=7.1, 3H),0.96 (t, J=7.4 Hz, 3H);

Example 32 Preparation of3,3-dimethyl-2-oxo-2-ethoxy-6-phenyl-1,2-benzoxaphosphole

A reaction was performed by the same method as in Example 17 except forusing 4-(phenyl)-dimethylbenzylphosphonic acid monoethyl ester (60.9 mg,0.2 mmol) instead of dimethylbenzylphosphonic acid monoethyl ester ofExample 17, thereby obtaining3,3-dimethyl-2-oxo-2-ethoxy-6-phenyl-1,2-benzoxaphosphole (45.9 mg, 76%)corresponding to the target compound.

¹H NMR (400 MHz, CDCl₃) δ 8.98 (s, 1H), 7.58-7.52 (m, 6H), 7.41 (t,J=7.5 Hz, 2H), 7.33-7.30 (m, 1H), 3.81-3.78 (m, 2H), 1.60 (d, J=15.8 Hz,6H), 1.11 (t, J=6.9 Hz, 3H)

Example 33 Preparation of3,3-dimethyl-2-oxo-2-ethoxy-6-(3-methyl)phenyl-1,2-benzoxaphosphole

A reaction was performed by the same method as in Example 17 except forusing 4-(3-methylphenyl)-dimethylbenzylphosphonic acid monoethyl ester(63.7 mg, 0.2 mmol) instead of dimethylbenzylphosphonic acid monoethylester of Example 17, thereby obtaining3,3-dimethyl-2-oxo-2-ethoxy-6-(3-methyl)phenyl-1,2-benzoxaphosphole(43.0 mg, 68%) corresponding to the target compound.

¹H NMR (400 MHz, CDCl₃) δ 7.78 (s, 1H), 7.57-7.52 (m, 4H), 7.41-7.36 (m,2H), 7.32-7.29 (m, 1H), 7.15-7.13 (m, 1H), 3.81-3.72 (m, 2H), 2.40 (s,3H), 1.59 (d, J=16.8 Hz, 6H), 1.10 (t, J=7.1 Hz, 3H)

Example 34 Preparation of3,3-dimethyl-2-oxo-2-ethoxy-6-(4-methyl)phenyl-1,2-benzoxaphosphole

A reaction was performed by the same method as in Example 17 except forusing 4-(4-methylphenyl)-dimethylbenzylphosphonic acid monoethyl ester(63.7 mg, 0.2 mmol) instead of dimethylbenzylphosphonic acid monoethylester of Example 17, thereby obtaining3,3-dimethyl-2-oxo-2-ethoxy-6-(4-methyl)phenyl-1,2-benzoxaphosphole(44.9 mg, 71%) corresponding to the target compound.

¹H NMR (400 MHz, CDCl₃) δ 7.45-7.43 (m, 2H), 7.30-7.28 (m, 1H), 7.25 (s,1H), 7.23-7.20 (m, 3H), 4.37-4.28 (m, 2H), 2.39 (s, 3H), 1.55 (dd,J=17.6, 2.6 Hz, 6H), 1.37 (t, J=7.1 Hz, 3H)

Example 35 Preparation of3,3-dimethyl-2-oxo-2-ethoxy-6-(4-tert-butyl)phenyl-1,2-benzoxaphosphole

A reaction was performed by the same method as in Example 17 except forusing 4-(4-t-butylphenyl)-dimethylbenzylphosphonic acid monoethyl ester(72.1 mg, 0.2 mmol) instead of dimethylbenzylphosphonic acid monoethylester of Example 17, thereby obtaining3,3-dimethyl-2-oxo-2-ethoxy-6-(4-tert-butyl)phenyl-1,2-benzoxaphosphole(53.0 mg, 74%) corresponding to the target compound.

¹H NMR (400 MHz, CDCl₃) δ 7.50-7.45 (m, 4H), 7.32-7.30 (m, 1H),7.22-7.20 (m, 2H), 4.39-4.28 (m, 2H), 1.55 (dd, J=17.6, 2.1 Hz, 6H),1.37 (t, J=7.0 Hz, 3H), 1.35 (s, 9H)

Example 36 Preparation of3,3-dimethyl-2-oxo-2-ethoxy-6-(3-methoxy)phenyl-1,2-benzoxaphosphole

A reaction was performed by the same method as in Example 17 except forusing 4-(3-methoxyphenyl)-dimethylbenzylphosphonic acid monoethyl ester(66.9 mg, 0.2 mmol) instead of dimethylbenzylphosphonic acid monoethylester of Example 17, thereby obtaining3,3-dimethyl-2-oxo-2-ethoxy-6-(3-methoxy)phenyl-1,2-benzoxaphosphole(47.9 mg, 72%) corresponding to the target compound.

¹H NMR (400 MHz, CDCl₃) δ 7.35 (t, J=7.9 Hz, 1H), 7.33-7.30 (m, 1H),7.24-7.22 (m, 2H), 7.14-7.12 (m, 1H), 7.07-7.07 (m, 1H), 6.91 (ddd,J=8.2, 2.6, 0.9 Hz, 1H), 4.38-4.28 (m, 2H), 3.86 (s, 3H), 1.55 (dd,J=17.6, 2.6 Hz, 6H), 1.38 (t, J=7.1 Hz, 3H)

Example 37 Preparation of3,3-dimethyl-2-oxo-2-ethoxy-6-(4-methoxy)phenyl-1,2-benzoxaphosphole

A reaction was performed by the same method as in Example 17 except forusing 4-(4-methoxyphenyl)-dimethylbenzylphosphonic acid monoethyl ester(66.9 mg, 0.2 mmol) instead of dimethylbenzylphosphonic acid monoethylester of Example 17, thereby obtaining3,3-dimethyl-2-oxo-2-ethoxy-6-(4-methoxy)phenyl-1,2-benzoxaphosphole(36.6 mg, 55%) corresponding to the target compound.

¹H NMR (400 MHz, CDCl₃) δ 7.50-7.47 (m, 2H), 7.28-7.26 (m, 1H),7.21-7.19 (m, 2H), 6.99-6.95 (m, 2H), 4.37-4.28 (m, 2H), 3.85 (s, 3H),1.55 (dd, J=17.6, 2.4 Hz, 6H), 1.38 (t, J=7.1 Hz, 3H)

Example 38 Preparation of3,3-dimethyl-2-oxo-2-ethoxy-6-(4-chloro)phenyl-1,2-benzoxaphosphole

A reaction was performed by the same method as in Example 17 except forusing 4-(4-chlorophenyl)-dimethylbenzylphosphonic acid monoethyl ester(67.8 mg, 0.2 mmol) instead of dimethylbenzylphosphonic acid monoethylester of Example 17, thereby obtaining3,3-dimethyl-2-oxo-2-ethoxy-6-(4-chloro)phenyl-1,2-benzoxaphosphole(49.8 mg, 74%) corresponding to the target compound.

¹H NMR (400 MHz, CDCl₃) δ 7.57-7.49 (m, 6H), 7.40-7.37 (m, 2H), 6.84 (s,1H), 3.82-3.75 (m, 2H), 1.59 (d, J=16.8 Hz, 6H), 1.11 (t, J=7.1 Hz, 3H)

Example 39 Preparation of 3,3-dimethyl-2-oxo-2-ethoxy-6-(3,5-dimethyl)phenyl-1,2-benzoxaphosphole

A reaction was performed by the same method as in Example 17 except forusing 4-(3,5-dimethylphenyl)-dimethylbenzylphosphonic acid monoethylester (66.5 mg, 0.2 mmol) instead of dimethylbenzylphosphonic acidmonoethyl ester of Example 17, thereby obtaining3,3-dimethyl-2-oxo-2-ethoxy-6-(3,5-dimethyl) phenyl-1,2-benzoxaphosphole(44.9 mg, 68%) corresponding to the target compound.

¹H NMR (400 MHz, CDCl₃) δ 7.30-7.28 (m, 1H), 7.21-7.19 (m, 1H), 7.15 (s,2H), 7.00 (s, 1H), 4.37-4.28 (m, 2H), 2.37 (s, 6H), 1.55 (dd, J=17.6,2.6 Hz, 6H), 1.37 (t, J=7.1 Hz, 3H)

Example 40 Preparation of 6-ethoxy-6H-dibenz c,e]oxaphosphorin-6-oxide

After Pd(OAc)₂ (4.5 mg, 0.02 mmol), PhI(OAc)₂ (128.8 mg, 0.4 mmol), KOAc(39.3 mg, 0.4 mmol), N-acetyl-L-leucine (10.4 mg, 0.06 mmol),1,1′-biphenylphosphonic acid monomethyl ester (52.4 mg, 0.2 mmol), andt-BuOH (2.5 mL) were put into a V-vial, the V-vial was covered with acap and the mixture was stirred and heated at 100 r for 12 hours. Afterthe reactant was extracted with dichloromethane, filtered using celite,and dried over MgSO4, the solvent was concentrated and removed, and theresultant was separated using column chromatography (ethylacetate:hexane=1:1), thereby obtaining6-ethoxy-6H-dibenz[c,e]oxaphosphorin-6-oxide (28.9 mg, 0.111 mmol, 55%).

¹H NMR (400 MHz, CDCl₃, 25° C., TMS): =8.00-7.93 (m, 3H), 7.74-7.70 (m,1H), 7.55-7.50 (m, 1H), 7.41-7.37 (m, 1H), 4.26-4.19 (m, 2H), 1.28 (t,J=7.1 Hz, 3H)

Example 41 Preparation of6-ethoxy-1-methyl-6H-dibenz[c,e]oxaphosphorin-6-oxide

A reaction was performed by the same method as in Example 40 except forusing 2′-methyl-1,1′-biphenylphosphonic acid monoethyl ester (55.2 mg,0.2 mmol) instead of 1,1′-biphenylphosphonic acid monoethyl ester ofExample 40, thereby obtaining6-ethoxy-1-methyl-6H-dibenz[c,e]oxaphosphorin-6-oxide (28.9 mg, 0.111mmol, 55%) corresponding to the target compound.

¹H NMR (400 MHz, CDCl₃)=8.01 (ddd, J=15.0, 7.5, 1.1 Hz, 1H), 7.84 (t,J=7.2 Hz, 3H), 7.70-7.66 (m, 1H), 7.52-7.48 (m, 1H), 7.28-7.24 (m, 1H),7.12 (d, J=17.9 Hz, 1H), 4.29-4.14 (m, 2H), 2.70 (s, 3H), 1.25 (t, J=7.1Hz, 3H)

Example 42 Preparation of6-ethoxy-2-methyl-6H-dibenz[c,e]oxaphosphorin-6-oxide

A reaction was performed by the same method as in Example 40 except forusing 3′-methyl-1,1′-biphenylphosphonic acid monoethyl ester (55.2 mg,0.2 mmol) instead of 1,1′-biphenylphosphonic acid monoethyl ester ofExample 40, thereby obtaining6-ethoxy-2-methyl-6H-dibenz[c,e]oxaphosphorin-6-oxide (28.9 mg, 0.111mmol, 55%) corresponding to the target compound.

¹H NMR (400 MHz, CDCl₃)=8.00-7.93 (m, 2H), 7.72-7.68 (m, 2H), 7.52-7.48(m, 1H), 7.18 (d, J=8.3 Hz, 1H), 7.12 (d, J=8.3 Hz, 1H), 4.24-4.17 (m,2H), 2.41 (s, 3H), 1.27 (t, J=7.1 Hz, 3H)

Example 43 Preparation of6-ethoxy-3-methyl-6H-dibenz[c,e]oxaphosphorin-6-oxide

A reaction was performed by the same method as in Example 40 except forusing 4′-methyl-1,1′-biphenylphosphonic acid monoethyl ester (55.2 mg,0.2 mmol) instead of 1 r-biphenylphosphonic acid monoethyl ester ofExample 40, thereby obtaining6-ethoxy-3-methyl-6H-dibenz[c,e]oxaphosphorin-6-oxide (28.9 mg, 0.111mmol, 55%) corresponding to the target compound.

¹H NMR (400 MHz, CDCl₃) δ 8.00-7.91 (m, 2H), 7.81 (d, J=8.1 Hz, 1H),7.70 (t, J=7.8 Hz, 1H), 7.50-7.46 (m, 1H), 7.08 (d, J=8.2 Hz, 1H), 7.05(s, 1H), 4.25-4.17 (m, 2H), 2.40 (s, 3H), 1.28 (t, J=7.1 Hz, 3H)

Example 44 Preparation of6-ethoxy-3-tert-butyl-6H-dibenz[c,e]oxaphosphorin-6-oxide

A reaction was performed by the same method as in Example 40 except forusing 4′-t-butyl-1,1′-biphenylphosphonic acid monoethyl ester (63.6 mg,0.2 mmol) instead of 1,1′-′ biphenylphosphonic acid monoethyl ester ofExample 40, thereby obtaining6-ethoxy-3-tert-butyl-6H-dibenz[c,e]oxaphosphorin-6-oxide (28.9 mg,0.111 mmol, 55%) corresponding to the target compound.

¹H NMR (400 MHz, CDCl₃) δ 7.97-7.92 (m, 2H), 7.85 (d, J=8.4 Hz, 1H),7.72-7.67 (m, 1H), 7.51-7.46 (m, 1H), 7.29 (dd, J=8.4, 1.8 Hz, 1H), 7.23(d, J=2.0 Hz, 1H), 4.26-4.19 (m, 2H), 1.35 (s, 9H), 1.29 (t, J=7.1 Hz,3H)

Example 45 Preparation of6-ethoxy-3-methoxy-6H-dibenz[c,e]oxaphosphorin-6-oxide

A reaction was performed by the same method as in Example 40 except forusing 4′-methoxy-1,1′-biphenylphosphonic acid monoethyl ester (58.4 mg,0.2 mmol) instead of 1,1′-biphenylphosphonic acid monoethyl ester ofExample 40, thereby obtaining6-ethoxy-3-methoxy-6H-dibenz[c,e]oxaphosphorin-6-oxide (28.9 mg, 0.111mmol, 55%) corresponding to the target compound.

¹H NMR (400 MHz, CDCl₃) δ 7.95 (ddd, J=14.6, 7.6, 1.1 Hz, 1H), 7.89-7.82(m, 2H), 7.70-7.66 (m, 1H), 7.47-7.43 (m, 1H), 6.84 (dd, J=8.8, 2.6 Hz,1H), 6.76 (d, J=2.6 Hz, 1H), 4.26-4.18 (m, 2H), 3.87 (s, 3H), 1.29 (t,J=7.1 Hz, 3H)

Example 46 Preparation of5-ethoxy-2,3-dimethoxy-6H-dibenz[c,e]oxaphosphorin-5-oxide

A reaction was performed by the same method as in Example 40 except forusing 3′,4′-dimethoxy-1,1′-biphenylphosphonic acid monoethyl ester (64.4mg, 0.2 mmol) instead of 1,1′-biphenylphosphonic acid monoethyl ester ofExample 40, thereby obtaining5-ethoxy-2,3-dimethoxy-6H-dibenz[c,e]oxaphosphorin-5-oxide (28.9 mg,0.111 mmol, 55%) corresponding to the target compound.

¹H NMR (400 MHz, CDCl₃) δ 7.95 (ddd, J=14.6, 7.5, 1.0 Hz, 1H), 7.83 (t,J=7.2 Hz, 1H), 7.69 (t, J=7.8 Hz, 1H), 7.48-7.43 (m, 1H), 7.32 (s, 1H),4.25-4.18 (m, 2H), 3.95 (d, J=14.5 Hz, 6H), 1.29 (t, J=7.1 Hz, 3H)

Example 47 Preparation of6-ethoxy-3-phenyl-6H-dibenz[c,e]oxaphosphorin-6-oxide

A reaction was performed by the same method as in Example 40 except forusing 4′-phenyl-1,1′-biphenylphosphonic acid monoethyl ester (67.6 mg,0.2 mmol) instead of 1 r-biphenylphosphonic acid monoethyl ester ofExample 40, thereby obtaining6-ethoxy-3-phenyl-6H-dibenz[c,e]oxaphosphorin-6-oxide (28.9 mg, 0.111mmol, 55%) corresponding to the target compound.

¹H NMR (400 MHz, CDCl₃) δ 8.02 (m, 3H), 7.75-7.71 (m, 1H), 7.66-7.63 (m,2H), 7.55-7.46 (m, 5H), 7.43-7.39 (m, 1H), 4.29-4.21 (m, 2H), 1.30 (t,J=7.1 Hz, 3H)

Example 48 Preparation of5-ethoxy-5H-benzo[c]naphtho[2,3-e][1,2]oxaphosphorin-5-oxide

A reaction was performed by the same method as in Example 40 except forusing 2-(naphthalene-2-yl)phenylphosphonic acid monoethyl ester (62.4mg, 0.2 mmol) instead of L biphenylphosphonic acid monoethyl ester ofExample 40, thereby obtaining 5-ethoxy-5H-benzo[c]naphtho[2,3-e][1,2]oxaphosphorin-5-oxide (28.9 mg, 0.111 mmol, 55%) corresponding to thetarget compound.

¹H NMR (400 MHz, CDCl₃) δ 8.40 (s, 1H), 8.13 (t, J=7.2 Hz, 1H), 8.02(ddd, J=14.6, 7.5, 1.0 Hz, 1H), 7.90 (d, J=8.1 Hz, 1H), 7.80 (d, J=8.1Hz, 1H), 7.76-7.73 (m, 1H), 4.28-4.20 (m, 2H), 1.26 (t, J=7.1 Hz, 3H)

Example 49 Preparation of5-ethoxy-5H-benzo[c]naphtho[1,2-e][1,2]oxaphosphorin-5-oxide

A reaction was performed by the same method as in Example 40 except forusing 2-(naphthalene-1-yl)phenylphosphonic acid monoethyl ester (62.4mg, 0.2 mmol) instead of 1,1′-biphenylphosphonic acid monoethyl ester ofExample 40, thereby obtaining5-ethoxy-5H-benzo[c]naphtho[1,2-e][1,2]oxaphosphorin-5-oxide (28.9 mg,0.111 mmol, 55%) corresponding to the target compound.

¹H NMR (400 MHz, CDCl₃) δ 8.52 (d, J=8.5 Hz, 1H), 8.17 (t, J=7.0 Hz,1H), 8.08 (ddd, J=14.8, 7.5, 0.8 Hz, 1H), 7.90 (dd, J=14.3, 8.0 Hz, 2H),7.74 (t, J=7.8 Hz, 1H), 7.60-7.49 (m, 3H), 7.38 (d, J=8.8 Hz, 1H),4.30-4.15 (m, 2H), 1.22 (t, J=7.1 Hz, 3H)

Example 50 Preparation of6-ethoxy-1-fluoro-6H-dibenz[c,e]oxaphosphorin-6-oxide

A reaction was performed by the same method as in Example 40 except forusing 2′-fluoro-1,1′-biphenylphosphonic acid monoethyl ester (56.0 mg,0.2 mmol) instead of 1,1′-biphenylphosphonic acid monoethyl ester ofExample 40, thereby obtaining6-ethoxy-1-fluoro-6H-dibenz[c,e]oxaphosphorin-6-oxide (28.9 mg, 0.111mmol, 55%) corresponding to the target compound.

¹H NMR (400 MHz, CDCl₃) δ 8.27 (t, J=7.3 Hz, 1H), 8.04-8.00 (m, 1H),7.72 (t, J=7.8 Hz, 1H), 7.57-7.52 (m, 1H), 7.09-7.01 (m, 2H), 4.28-4.20(m, 2H), 1.28 (t, J=7.1 Hz, 3H)

Example 51 Preparation of6-ethoxy-2-chloro-6H-dibenz[c,e]oxaphosphorin-6-oxide

A reaction was performed by the same method as in Example 40 except forusing 3′-chloro-1,1′-biphenylphosphonic acid monoethyl ester (59.2 mg,0.2 mmol) instead of biphenylphosphonic acid monoethyl ester of Example40, thereby obtaining6-ethoxy-2-chloro-6H-dibenz[c,e]oxaphosphorin-6-oxide (28.9 mg, 0.111mmol, 55%) corresponding to the target compound.

¹H NMR (400 MHz, CDCl₃) δ 8.00 (ddd, J=14.6, 7.6, 1.1 Hz, 1H), 7.94-7.90(m, 2H), 7.76-7.72 (m, 1H), 7.59-7.52 (m, 1H), 7.36-7.33 (m, 1H), 7.19(d, J=8.6 Hz, 1H), 4.27-4.20 (m, 2H), 1.29 (t, J=7.1 Hz, 3H)

Example 52 Preparation of6-ethoxy-3-chloro-6H-dibenz[c,e]oxaphosphorin-6-oxide

A reaction was performed by the same method as in Example 40 except forusing 4′-chloro-1,1′-biphenylphosphonic acid monoethyl ester (59.2 mg,0.2 mmol) instead of 1,1′-biphenyl phosphonic acid monoethyl ester ofExample 40, thereby obtaining6-ethoxy-3-chloro-6H-dibenz[c,e]oxaphosphorin-6-oxide (28.9 mg, 0.111mmol, 55%) corresponding to the target compound.

¹H NMR (400 MHz, CDCl₃) δ 8.00 (ddd, J=14.7, 7.6, 1.0 Hz, 1H), 7.92 (t,J=7.2 Hz, 1H), 7.90 (d, J=9.1 Hz, 1H), 7.75-7.70 (m, 1H), 7.57-7.52 (m,1H), 7.27-7.25 (m, 2H), 4.29-4.20 (m, 2H), 1.30 (t, J=7.1 Hz, 3H)

Example 53 Preparation of5-ethoxy-5H-benzo[c]thieno[2,3-e][1,2]oxaphosphorin-5-oxide

A reaction was performed by the same method as in Example 40 except forusing 2-(thiophen-2-yl)phenylphosphonic acid monoethyl ester (53.6 mg,0.2 mmol) instead of 1,1′-biphenylphosphonic acid monoethyl ester ofExample 40, thereby obtaining5-ethoxy-5-benzo[c]thieno[2,3-e][1,2]oxaphosphorin-5-oxide (28.9 mg,0.111 mmol, 55%) corresponding to the target compound.

¹H NMR (400 MHz, CDCl₃) δ 7.92 (ddd, J=14.1, 7.6, 0.7 Hz, 1H), 7.64-7.60(m, 1H), 7.51-7.47 (m, 1H), 7.44-7.39 (m, 1H), 7.26-7.25 (m, 1H),4.27-4.19 (m, 2H), 1.32 (t, J=7.1 Hz, 3H)

Example 54 Preparation of6-ethoxy-2,9-dimethyl-6H-dibenz[c,e]oxaphosphorin-6-oxide

A reaction was performed by the same method as in Example 40 except forusing 3′-methyl-5-methyl-1,1′-biphenylphosphonic acid monoethyl ester(58.0 mg, 0.2 mmol) instead of 1,1′-biphenylphosphonic acid monoethylester of Example 40, thereby obtaining6-ethoxy-2,9-dimethyl-6H-dibenz[c,e]oxaphosphorin-6-oxide (28.9 mg,0.111 mmol, 55%) corresponding to the target compound.

¹H NMR (400 MHz, CDCl₃) δ 7.86 (dd, J=14.4, 7.7 Hz, 1H), 7.76 (d, J=6.0Hz, 1H), 7.71 (d, J=1.5 Hz, 1H), 7.33-7.30 (m, 1H), 7.17 (d, J=8.3 Hz,1H), 7.10 (d, J=8.2 Hz, 1H), 4.21-4.14 (m, 2H), 2.50 (s, 3H), 2.41 (s,3H), 1.26 (t, J=7.1 Hz, 3H)

Example 55 Preparation of6-ethoxy-2,3-dimethoxy-9-methyl-6H-dibenz[c,e]oxaphosphorin-6-oxide

A reaction was performed by the same method as in Example 40 except forusing 3′-methyl-5-methyl-1,1′-biphenylphosphonic acid monoethyl ester(67.2 mg, 0.2 mmol) instead of 1,1′-biphenylphosphonic acid monoethylester of Example 40, thereby obtaining6-ethoxy-2,3-dimethoxy-9-methyl-6H-dibenz[c,e]oxaphosphorin-6-oxide(28.9 mg, 0.111 mmol, 55%) corresponding to the target compound.

¹H NMR (400 MHz, CDCl₃) δ 7.83 (dd, J=14.4, 7.7 Hz, 1H), 7.61 (d, J=6.0Hz, 1H), 7.31 (s, 1H), 7.28-7.26 (m, 1H), 6.74 (s, 1H), 4.23-4.15 (m,2H), 3.99 (s, 3H), 3.93 (s, 3H), 2.50 (s, 3H), 1.28 (t, J=7.1 Hz, 3H)

Example 56 Preparation of6-ethoxy-2-chloro-9-methyl-6H-dibenz[c,e]oxaphosphorin-6-oxide

A reaction was performed by the same method as in Example 40 except forusing 3′-chloro-5-methyl-1,1′-biphenylphosphonic acid monoethyl ester(62.0 mg, 0.2 mmol) instead of 1,1′-biphenylphosphonic acid monoethylester of Example 40, thereby obtaining6-ethoxy-2-chloro-9-methyl-6H-dibenz[c,e]oxaphosphorin-6-oxide (28.9 mg,0.111 mmol, 55%) corresponding to the target compound.

¹H NMR (400 MHz, CDCl₃) δ 7.90-7.84 (m, 2H), 7.71 (d, J=6.0 Hz, 1H),7.39-7.36 (m, 1H), 7.17 (d, J=8.7 Hz, 1H), 4.25-4.17 (m, 2H), 2.51 (s,3H), 1.28 (t, J=7.1 Hz, 3H)

Example 57 Preparation of6-ethoxy-2-methyl-8-fluoro-6H-dibenz[c,e]oxaphosphorin-6-oxide

A reaction was performed by the same method as in Example 40 except forusing 3′-methyl-1,1′-biphenyl-4-fluorophosphonic acid monoethyl ester(58.8 mg, 0.2 mmol) instead of 1,1′-biphenylphosphonic acid monoethylester of Example 40, thereby obtaining6-ethoxy-2-methyl-8-fluoro-6H-dibenz[c,e]oxaphosphorin-6-oxide (28.9 mg,0.111 mmol, 55%) corresponding to the target compound.

¹H NMR (400 MHz, CDCl₃) δ 7.98-7.92 (m, 1H), 7.68-7.61 (m, 2H), 7.38(td, J=12.8, 2.8 Hz, 1H), 7.18 (d, J=8.3 Hz, 1H), 7.12 (d, J=8.3 Hz,1H), 4.26-4.19 (m, 2H), 2.41 (s, 3H), 1.29 (t, J=7.1 Hz, 3H)

Example 58 Preparation of6-ethoxy-2,3-dimethoxy-8-fluoro-6H-dibenz[c,e]oxaphosphorin-6-oxide

A reaction was performed by the same method as in Example 40 except forusing 3′,4′-dimethoxy-4-fluoro-1,1′-biphenylphosphonic acid monoethylester (68.0 mg, 0.2 mmol) instead of 1,1′-biphenylphosphonic acidmonoethyl ester of Example 40, thereby obtaining6-ethoxy-2,3-dimethoxy-8-fluoro-6H-dibenz[c,e]oxaphosphorin-6-oxide(28.9 mg, 0.111 mmol, 55%) corresponding to the target compound.

¹H NMR (400 MHz, CDCl₃) δ 7.85-7.80 (m, 1H), 7.63 (ddd, J=15.7, 7.6, 2.7Hz, 1H), 7.38 (td, J=12.8, 2.6 Hz, 1H), 7.26 (s, 1H), 6.75 (s, 1H),4.28-4.20 (m, 2H), 4.00 (s, 3H), 3.93 (s, 3H), 1.31 (t, J=7.1 Hz, 3H)

Example 59 Preparation of6-ethoxy-2-chloro-8-fluoro-6H-dibenz[c,e]oxaphosphorin-6-oxide

A reaction was performed by the same method as in Example 40 except forusing 3′-chloro-4-fluoro-1,1′-biphenylphosphonic acid monoethyl ester(62.8 mg, 0.2 mmol) instead of 1,1′-biphenylphosphonic acid monoethylester of Example 40, thereby obtaining6-ethoxy-2-chloro-8-fluoro-6H-dibenz[c,e]oxaphosphorin-6-oxide (28.9 mg,0.111 mmol, 55%) corresponding to the target compound.

¹H NMR (400 MHz, CDCl₃) δ 7.94-7.89 (m, 1H), 7.84 (d, J=2.4 Hz, 1H),7.68 (ddd, J=15.7, 10.2, 2.8 Hz, 1H), 7.42 (td, J=12.8, 2.8 Hz, 1H),7.36-7.33 (m, 1H), 7.20 (d, J=8.7 Hz, 1H), 4.30-4.22 (m, 2H), 1.31 (t,J=7.1 Hz, 3H)

The cyclic phosphinate derivative according to the present invention mayhave pharmacological and physiological activities, be used as the basicskeleton of the natural material, and be used as the important rawmaterial or intermediate capable of being used in development of a newdrug, synthesis of various medicines, and the crop protection agentfield.

In addition, with the method of preparing a cyclic phosphinatederivative according to the present invention, the cyclic phosphinatederivatives in which various substituents are introduced may be preparedwith high yield through the simple synthetic process by performing theintramolecular carbon-oxygen coupling reaction on the phosphinic acidderivative in the presence of the palladium (Pd) catalyst, the oxidant,and the base.

What is claimed is:
 1. A cyclic phosphinate compound represented by thefollowing Chemical Formula 3:

in Chemical Formula 3, R¹ to R⁴ are each independently hydrogen,(C1-C20)alkyl, halo(C1-C20)alkyl, (C1-C20)alkoxy, (C6-C20)aryl, halogen,(C6-C20)aryloxy, or tri(C1-C20)alkylsilyl; R⁵ is (C1-C20)alkyl,(C1-C20)alkoxy, or (C6-C20)aryl; R¹¹ and R¹² are each independentlyhydrogen or (C1-C20)alkyl, or are linked to each other by(C1-C7)alkylene to form a spiro ring; and the alkyl and aryl of R¹ to R⁵are optionally substituted with a substituent selected from the groupconsisting of halogen, (C1-C20)alkyl, (C1-C20)alkoxy, andhalo(C1-C20)alkyl.
 2. The cyclic phosphinate compound of claim 1,wherein R¹ to R⁴ are each independently hydrogen, methyl, ethyl, propyl,butyl, pentyl, hexyl, trifluoromethyl, methoxy, ethoxy, propoxy, butoxy,pentyloxy, hexyloxy, phenyl, naphthyl, fluorenyl, chloro, bromo, fluoro,or trimethylsilyl (TMS), the phenyl, naphthyl, or fluorenyl of R¹ to R⁴are optionally substituted with a substituent selected from the groupconsisting of chloro, bromo, fluoro, methyl, ethyl, propyl, butyl,pentyl, hexyl, methoxy, ethoxy, propoxy, butoxy, pentyloxy, hexyloxy,and trifluoromethyl; R⁵ is methyl, ethyl, propyl, butyl, pentyl, hexyl,methoxy, ethoxy, propoxy, butoxy, pentyloxy, hexyloxy, phenyl, ornaphthyl, the phenyl or naphthyl of R⁵ are optionally substituted with asubstituent selected from the group consisting of chloro, bromo, fluoro,methyl, ethyl, propyl, butyl, pentyl, hexyl, methoxy, ethoxy, propoxy,butoxy, pentyloxy, hexyloxy, and trifluoromethyl; and R¹¹ and R¹² areeach independently methyl, ethyl, propyl, butyl, pentyl, or hexyl, orare linked to each other by butylene or pentylene to form a spiro ring.3. The cyclic phosphinate compound of claim 2, wherein it is selectedfrom the following compounds.


4. A method of preparing a cyclic phosphinate derivative characterizedby performing an intramolecular carbon-oxygen coupling reaction on aphosphinic acid derivative represented by the following Chemical Formula7 to prepare a cyclic phosphinate derivative represented by thefollowing Chemical Formula 3 in the presence of a palladium (Pd)catalyst, an oxidant, and a base:

in Chemical Formulas 3 and 7, R¹ to R⁴ are each independently hydrogen,(C1-C20)alkyl, halo(C1-C20)alkyl, (C1-C20)alkoxy, (C6-C20)aryl, halogen,(C6-C20)aryloxy, or tri(C1-C20)alkylsilyl; R⁵ is (C1-C20)alkyl,(C1-C20)alkoxy, or (C6-C20)aryl; R¹¹ and R¹² are each independently(C1-C20)alkyl, or are linked to each other by (C1-C7)alkylene to form aspiro ring; and the alkyl and aryl of R¹ to R⁵ are optionallysubstituted with a substituent selected from the group consisting ofhalogen, (C1-C20)alkyl, (C1-C20)alkoxy, and halo(C1-C20)alkyl.
 5. Themethod of preparing a cyclic phosphinate derivative of claim 4, whereinthe palladium (Pd) catalyst is one or two or more selected from thegroup consisting of PdCl₂, PdBr₂, Pd(OAc)₂, Pd(dba)₂, Pd₂(dba)₃,Pd₂dba₃.CHCl₃, Pd(PPh₃)₄, Pd(OTf)₂, Pd(OTf)₂.2H₂O, Pd(TFA)₂,PdCl₂(MeCN)₂, PdCl₂(PPh₃)₂, Pd(dppf)Cl₂, and [PdCl(C₃H₅)]₂.
 6. Themethod of preparing a cyclic phosphinate derivative of claim 4, whereina use amount of the palladium (Pd) catalyst is 0.01 to 0.5 equivalentswith respect to the phosphinic acid derivative represented by ChemicalFormula
 7. 7. The method of preparing a cyclic phosphinate derivative ofclaim 4, wherein the oxidant is one or two or more selected from thegroup consisting of CuCl, Cu₂O, CuO, Cu(OAc)₂, Cu(OTf)₂ [OTf:trifluoromethanesulfonate], CuCl₂, CuBr, CuI, Cu(acac)₂, Ag₂O, AgO,AgOAc, Ag₂CO₃, Na₂S₂O₈, K₂S₂O₈, NaOAc, BQ [BQ: benzoquinone], FeCl₃,Mn(OAc)₃.2H₂O, V₂O₅, PhI(OAc)₂, PhI(TFA)₂, IOAc, ozone, oxygen,(PhCO₂)₂, and 2,2,6,6-tetramethyl-1-piperidinyloxy (free radical,TEMPO).
 8. The method of preparing a cyclic phosphinate derivative ofclaim 4, wherein a use amount of the oxidant is 0.1 to 5.0 equivalentswith respect to the phosphinic acid derivative represented by ChemicalFormula
 7. 9. The method of preparing a cyclic phosphinate derivative ofclaim 4, wherein the base is one or two or more selected from the groupconsisting of KH₂PO₄, Na₂HPO₄.2H₂O, Na₂HPO₄, Na₂CO₃, NaH₂PO₄, LiOAc,Li₂CO₃, NaOAc, K₂HPO₄, K₃PO₄, K₂CO₃, CsF, KHCO₃, KOH, KF, KPF₆, KOAc,NaF, CsOAc, CsOPiv, LiPF₆, Li₃PO₄, LiF, and LiI.
 10. The method ofpreparing a cyclic phosphinate derivative of claim 4, wherein a useamount of the base is 0.5 to 3.0 equivalents with respect to thephosphinic acid derivative represented by Chemical Formula 7.